public int ping(String ip) {
    return InetAddress.getByName(host).isReachable(5000)?1:0;
}

String[] iparray = new String[500];
//......
for (int i=0; i<iparray.length; i++) {
    int result = ping(iparray[i]);
}

------解决方案--------------------

Java code

public int ping(String ip) {
    return InetAddress.getByName(ip).isReachable(5000)?1:0;
}

String[] iparray = new String[500];
//......
for (int i=0; i<iparray.length; i++) {
    int result = ping(iparray[i]);
}

------解决方案--------------------
采用多线程：
Java code

for (Integer i = 1; i <= station; i++) {
    String ip = pro.getPropertyValue("station" + i.toString(), "ip");
    MonitorThread myThread = new MonitorThread(i, ip);
    threads[i] = new Thread(myThread);
    threads[i].start();
}